The water flow rate used in
these experiments was 0.4 mL/min. This flow rate was
slow enough to ensure that equilibrium was obtained.
The solubility of alizarin was experimentally determined
as described for the same water temperatures used in
the extraction experiment, at 383, 443, and 493 °C. The
equilibrium concentrations of the alizarin solutions were
measured using a spectrophotometer (Genesys 20).